Some films grab your attention from the very first shot and don’t let go; Cradle Will Rock is a great example, starting on a high note and actually managing to top itself, becoming better and better as it goes along. Even the opening titles are startling: a superposition of a frivolous jazzy tune setting the time period and a title card, an icon in the style of Soviet agitprop art, replete with the image of a hammer and an anvil.

The opening that follows (it pretends to be one ten-minute shot, but is actually comprised of three elaborate tracking shots) is nothing short of masterful, a stunning sequence that manages to encapsulate the entire universe where the film takes place, the main characters, and the complexity of interweaving action and meaning. It also cannily incorporates a newsreel of the day, making an effortless historical introduction and rendering the opening text crawl rather unnecessary.

For a good part of its running time, Cradle Will Rock feels like the film Magnolia wanted to be but couldn’t (from an artistic point of view; the meaning of these two films is vastly different). It is an epic canvas with a multitude of characters, linked together in unexpected ways, and multiple plot strands breathlessly edited together, each reinforcing the other ones. It’s also visually arresting (something that I really didn’t expect, since writer/director Tim Robbins’s previous film, Dead Man Walking, was consistently visually drab), with glowing cinematography and frequent breathtaking moments.

The whole story is centered around a federally-funded theatre project, which served to simultaneously cut unemployment among the actors -- and bring art into the masses. One play in production is a musical by Mark Blitzstein (Hank Azaria, who fills the role perfectly). The play, “The Cradle Will Rock,” is directed by none other than Orson Welles (Angus MacFadyen, doing entirely too much clowning). Robbins uses this merely as a central strand in his brightly-colored social tapestry, which reaches such far-off figures, real and invented, as Nelson Rockefeller (John Cusack, sporting a much better haircut than that he had in Being John Malkovich) and a bitter ventriloquist, Tommy Crickshaw (Bill Murray, in another stunning portrayal of middle-aged disillusionment, akin to his Mr. Blume from Rushmore).

It is simply impossible to comment on all the performers in Cradle Will Rock; not only does the cast list read as a virtual who’s-who of contemporary acting talent, but they are almost all consistently excellent; I can single out just a few. Emily Watson by now should have a copyright on the psychologically wounded young woman with strong moral fiber, but this doesn’t detract from the fact that here, as always, she nails every single moment her character is on screen. Cary Elwes (The Princess Bride), on the other hand, in the past was either miscast or simply not very good; here he plays the musical’s producer, a walking caricature, to be sure, but Elwes makes it a perfectly believable -- not to mention downright hilarious -- caricature. Vanessa Redgrave is even funnier, playing a noble countess as giddy and excitable as a little girl at a party.

The most impressive performance, though -- and the most downstated one -- is courtesy of one the least known names in the cast, Cherry Jones, who plays Hallie Flanagan, the Theatre Project’s supervisor. One of the best scenes in the film has her interrogated by a Washington committee which suspects her of Communist Propaganda (and that twenty years before McCarthy). Robbins uses the real historical transcripts of this deposition, and makes them sound both funny and disturbing. The delicious irony is that the boneheaded politicians accused the Theatre Project of communist incliations, while themselves trying to control art in a true communist tradition.

In case all of the above sounds too high-minded, make no mistake: Cradle Will Rock packs plenty of punch, with its clearly-cut (but perfectly distinct) characters, and crowd-pleasing dynamics. The main conflict might feel a bit too spelled-out at some times, but very soon it becomes clear that Robbins is working in the very genre he’s championing, the genre of socially responsible art, in this case mostly theatre.

The only time when Cradle looses some momentum is during its climactic performance of the titular musical. By this time, most of subplots already merged into one or two, so there is less possibility to cut between the strands. There’s only so many times one can cut to Redgrave’s character laughing and applauding before its starts to feel somewhat forced.

But the end picks up again, when it becomes abundantly clear what precisely won in the war between art for the working class and art for the rich. Robbins makes his point with a wildly unexpected, sublimely funny, and witheringly sardonic final shot; a fitting conclusion for a film that was immensely entertaining from its first frame to its last.